DataTransfer: setData() method

The DataTransfer.setData() method sets the drag operation's drag data to the specified data and type. If data for the given type does not exist, it is added at the end of the drag data store, such that the last item in the types list will be the new type. If data for the given type already exists, the existing data is replaced in the same position. That is, the order of the types list is not changed when replacing data of the same type.

Example data types are text/plain and text/uri-list.

Syntax

js

setData(format, data)

Parameters

format

A string representing the type of the drag data to add to the drag object.

data

A string representing the data to add to the drag object.

Return value

None (undefined).

Examples

Dragging an element

In this example we can drag a <p> element into a target <div> element.

  • In the dragstart handler, we use setData() to add the id of the <p> element to the DataTransfer object.
  • In the drop handler we retrieve the id and use it to move the <p> element into the target.

HTML

html

<div>
  <p id="source" draggable="true">
    Select this element, drag it to the drop zone and then release the selection
    to move the element.
  </p>
</div>
<div id="target">Drop Zone</div>

<button id="reset">Reset example</button>

CSS

css

div {
  margin: 0.5em 0;
  padding: 2em;
}

#target,
#source {
  border: 1px solid black;
  padding: 0.5rem;
}

.dragging {
  background-color: pink;
}

JavaScript

js

const source = document.querySelector("#source");
source.addEventListener("dragstart", (ev) => {
  console.log("dragStart");
  // Change the source element's background color
  // to show that drag has started
  ev.currentTarget.classList.add("dragging");
  // Clear the drag data cache (for all formats/types)
  ev.dataTransfer.clearData();
  // Set the drag's format and data.
  // Use the event target's id for the data
  ev.dataTransfer.setData("text/plain", ev.target.id);
});
source.addEventListener("dragend", (ev) =>
  ev.target.classList.remove("dragging")
);

const target = document.querySelector("#target");
target.addEventListener("dragover", (ev) => {
  console.log("dragOver");
  ev.preventDefault();
});
target.addEventListener("drop", (ev) => {
  console.log("Drop");
  ev.preventDefault();
  // Get the data, which is the id of the source element
  const data = ev.dataTransfer.getData("text");
  const source = document.getElementById(data);
  ev.target.appendChild(source);
});

const reset = document.querySelector("#reset");
reset.addEventListener("click", () => document.location.reload());

Result

Specifications

Specification
HTML Standard
# dom-datatransfer-setdata-dev

Browser compatibility

BCD tables only load in the browser

See also